1. Technical Field
The present invention relates generally to devices for laying pipe and, more specifically, to a device that is capable of auto-advancement, laying and joining pipe.
2. Background of the Invention
The process of laying sections of pipe for an underground pipeline involves the excavation of a trench to a desired depth followed by placement and positioning of pipe in the trench. When a bell and spigot pipe is being installed, the lengths are typically joined by applying mechanical pressure to a most recently laid section of pipe in order to engage the spigot end of that length with the bell end of a previously laid length. This method involves placing one or more workers in the trench to guide a lowered section of pipe into contact with a previously installed section. The workers must also disengage rigging from the pipe that was used in lowering the length into the trench. Once a pipe length is positioned in the trench, it is manually joined to a preceding pipe length. In deep trenches, a work crew commonly works within the confines of a trench shoring box that provides increased safety in the trench working condition.
Excavation and placement functions are typically performed by a single piece of equipment, an excavator. The excavator is a relatively costly piece of equipment, often track mounted, that performs primarily an excavation function. One disadvantage of the current popular method is the fact that a costly piece of equipment is oftentimes moved between tasks, excavation and pipe installation, that may otherwise proceed at different rates. Additionally, where shoring is required it is often moved along the length of the trench by the excavator as the pipeline advances requiring yet a third function or task of the excavator.
Devices, including excavators that position or otherwise place pipe at the bottom of a trench, pose a number of disadvantages. These devices are positioned outside the trench and typically place pipe by maneuvering along a top edge of the trench over tailings that have been placed alongside the trench during excavation. These surfaces are rarely, if ever, flat and therefore make the task of placement more difficult. Additionally, activity at grade level, depending on soil conditions, may increase a probability of trench collapse.
Advantage may therefore be found in providing an auto-advancing device that is capable of laying and joining pipe in a trench. Additional advantage may be found in providing an apparatus that auto-advances along a pre-excavated trench, laying and joining pipe in the trench. Additional advantage may be found in providing a method for advancing a device for feeding, laying and joining pipe along a trench. Advantage may also be found in providing a pipe installation device that is capable of auto-advancing along the floor of an excavated trench by engagement with at least one surface of the trench selected from a group of trench surfaces including a floor and two generally opposing sidewalls defining the trench.